1. Field of the Invention
This invention relates to joint prostheses and to methods of placing joint prostheses in human or animal bodies.
2. Discussion of Prior Art
Replacement of worn out, damaged or diseased joints of human or animal bodies with artificial joint prostheses or components is an established medical procedure. Conventional joint prostheses or components for use in such procedures, which have been designed for virtually all types of joints, generally comprise component parts of the same or similar shape or form as all or part of the natural joint they are designed to replace. For example, the condyle surfaces of a knee joint may be replaced with metal plates of the same shape as the surfaces they replace. Alternatively, a whole joint may be replaced with a metal joint prosthesis taking a generally similar form to the original knee.
This conventional approach to joint replacement has various disadvantages. Firstly, the component parts of such joint prostheses are usually large and require invasive surgical procedures to put the prosthetic components in place. Secondly, although the artificial component parts may have the same shape as the original natural joints, they cannot provide the same function as they are made from artificial material rather than bone and/or body tissues. For example, when the condyle surface of a knee is replaced the articular cartilage is removed and the new artificial surface will not be lubricated in the same way as a natural knee. This results in wear both of the artificial components and the body tissue surrounding or coming into contact with the artificial component.